Smoking Article Wrapper

ABSTRACT

A smoking article wrapper includes at least one coated surface area and at least one non-coated surface area, wherein the smoking article wrapper is combustible and provides a mean volumetric flow rate of at least 40 CU, wherein the at least one coated surface area provides a glossiness of at least 4 GU, the at least one non-coated surface area provides a glossiness of less than 4 GU and the difference of glossiness between the at least one coated surface area and the at least one non-coated surface area is more than 2 GU. A smoking article includes such a smoking article wrapper. A method for producing a smoking article includes such a smoking article wrapper by printing a polymer on parts of the smoking article wrapper by flexography.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/EP2020/073315, filed Aug. 20, 2020, published in English, which claims priority to European Application No. 19193384.5 filed Aug. 23, 2019, the disclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a smoking article wrapper and a method for producing such a smoking article wrapper according to the preamble of present claims 1 and 13. Furthermore, the present invention relates to a smoking article comprising a smoking article wrapper according to the preamble of present claim 1.

Smoking articles such as cigarettes are consumer goods produced in large quantities. They usually comprise a tobacco rod formed by wrapping tobacco cut filler with a paper based wrapper in a longitudinally extending substantially cylindrical rod. Beyond their primary tobacco wrapping function, paper based smoking article wrappers also often form a communication support for manufacturers and may comprise various printed designs, colours and/or markings (watermarks, embossing etc. . . . ), which may form part of branding features allowing consumers to recognize products among others. Thus, it is highly appreciated to provide visual effects on the cigarette paper to allow delimitation with respect to cigarettes from other brands or to provide premium appearance of the cigarettes and/or the cigarette paper. Especially highly reflective or shiny patterns may be desired, which are not obtainable through existing embossing techniques.

In the following the terms “smoking article” and “cigarette” are used synonymously. Some embodiments of the invention are only described for a cigarette or a cigarette paper. However, also these embodiments should be considered to be applicable and disclosed also for any other smoking article and/or smoking article wrapper.

From document WO 2016 208 065 A1 it is known, that a shiny effect could be achieved by calendaring. However, this technology can't be applied partially and results in a homogeneous appearance of the surface of the cigarette paper.

Document EP 3 312 340 A1 discloses a method and an apparatus for making a cigarette paper having a glossiness of at least 10% or higher. The high glossiness is achieved by supercalendering a paper web containing a filler for increasing gloss.

From document US 2002/062834 A1 a low sidestream smoke cigarette is known. Such a cigarette comprises a combustible treatment paper having a sidestream smoke treatment composition comprising an oxygen storage and donor metal oxide oxidation catalyst and an essentially non-combustible finely divided porous particulate adjunct for said catalyst. The adjunct has preferably an average particle size of 1-30 μm and a high surface area of 20 m²/g.

Surface treatments of cigarette papers are very limited since a defined permeability has to be guaranteed. The permeability of cigarette papers is defined as the measure of the volume of air that flows through a specified area of cigarette paper in a given unit of time. It is measured in CORESTA units (C.U.). A CORESTA Unit is defined as “the volumetric flow rate of air (cm³ min⁻¹) passing through a 1 cm² sample of substrate at an applied pressure difference of 1 kPa”. For most cigarette papers it is desired that they provide a mean volumetric flow rate of at least 40 cm³min⁻¹ air passing through sample of 1 cm² of this cigarette paper at an applied pressure difference of 1 kPa (or 40 C.U.).

Furthermore, cigarette papers with semi-transparent segments are known. However, the semi-transparent segments have the disadvantage that the brownish tobacco colour could be seen in these areas. The brownish areas could be considered to be dirty or even unhygienic.

BRIEF SUMMARY OF THE INVENTION

It is therefore the objective of the present invention to provide a cigarette paper with highly reflective or shiny patterns and a method for producing such a cigarette paper. Furthermore, it is an objective of the present invention to provide a smoking article comprising such a cigarette paper.

The afore-mentioned problems are solved by a cigarette paper comprising at least one coated surface area and at least one non-coated surface area, wherein the cigarette paper is combustible and provides a mean volumetric flow rate of at least 40 cm³min⁻¹ air passing through a sample of 1 cm² of this cigarette paper at an applied pressure difference of 1 kPa, wherein the at least one coated surface area of the cigarette paper provides a glossiness of at least 4 GU according to DIN EN ISO 2813:2015, the at least one non-coated surface area provides a glossiness of less than 4 GU according to DIN EN ISO 2813:2015 and the difference of glossiness between the at least one coated surface area and the at least one non-coated surface area is more than 2 GU according to DIN EN ISO 2813:2015.

It has been found, that even the relatively low glossiness of at least 4 GU according to DIN EN ISO 2813:2015 could be easily recognized by the consumer if the difference of glossiness with respect to the at least one non-coated surface area was more than 2 GU according to DIN EN ISO 2813:2015. However, a greater difference of glossiness (e.g. at least 4 GU, 7 GU, 10 GU, 20 GU or even more) between the at least one coated surface area and the at least one non-coated surface area would even increase the effect. However, it has been found that the pattern could be recognized by the consumer especially well if the glossiness of the at least one non-coated surface area was less than 4 GU according to DIN EN ISO 2813:2015. Those cigarette papers provide an enhanced visual appearance and could easily be recognized by the consumer.

In a preferred embodiment of the cigarette paper, the at least one coated surface area of the cigarette paper provides a glossiness between 4-10 GU, preferably between 5-10 GU according to DIN EN ISO 2813:2015. It has been found that a glossiness in this range could be provided by the method as described below and is sufficient to provide information to the consumer or to allow delimitation with respect to cigarettes from other brands or to provide premium appearance of the cigarettes and/or the cigarette paper. An even higher glossiness of more than 10 GU would even increase the effect, but it has been found, that for most applications a glossiness between 4-10 GU is sufficient. A higher glossiness usually requires higher amounts of coating material, which limits the permeability of the cigarette paper and/or increases costs.

In a preferred embodiment of the cigarette paper, the at least one non-coated surface area provides a glossiness between 1-4 GU, preferably between 1-3 GU according to DIN EN ISO 2813:2015. GU values in the above-mentioned range are especially suitable since the established appearance of an uncoated cigarette paper could be maintained but the required difference of the GU with respect to the coated surface area could easily be established.

As pointed out above with respect to some known cigarette papers, locally increased opacity could result in disadvantages. Thus, in a preferred embodiment of the cigarette paper, the difference of opacity of the coated surface area and the non-coated surface area of the cigarette paper is less than 2%, preferably less than 1%. By such a homogeneous opacity it could be avoided that the brownish tobacco shines through the cigarette paper locally. The unfavorable dirty or even unhygienic appearance could be avoided.

To avoid the brownish tobacco from shining through the cigarette paper locally, the opacity of the coated surface area of the cigarette paper is preferably more than 70%, preferably more than 72%, more preferably more than 73%. Especially in combination with the glossiness of at least 4 GU of the at least one coated surface area of the cigarette paper this opacity provides a high-value and/or premium-quality appearance of the cigarette paper. Even without any written or illustrative information for the consumer, this high-value and/or premium-quality appearance allows recognition of cigarettes with this cigarette paper.

In a preferred embodiment of the cigarette paper, the percentage of the coated surface area is less than 80% of the total surface area of the cigarette paper, preferably less than 50%, more preferably in the range between 20% and 50%. Coatings of this dimension are preferred since these percentages allow for writings and/or illustrations on the cigarette paper. Furthermore, the required permeability of the cigarette paper is maintained. Higher percentages of the coated area result at least in some cases in reduced permeability of the cigarette paper, which could result in unwanted ignition of the cigarette.

In a preferred embodiment of the cigarette paper, the coated surface area comprises a coating of 0.5 to 20 g/m², preferably of 2 to 15 g/m², more preferably of 4 to 10 g/m². It has been found, that at these application weights the desired glossiness could be provided at minimal material costs. Furthermore, higher amounts of coating material have shown to reduce the permeability of the cigarette paper in some cases. In contrast thereto the preferred application weights as defined above ensure the required permeability of the cigarette paper.

In a preferred embodiment of the cigarette paper, the coated surface area comprises a polymer as coating agent. Polymers provide the desired glossiness at minimal application weights. Furthermore, at least some polymers could be thermally decomposed without any residues and/or are heat resistant and are incombustible at the temperatures occurring in a cigarette. Any of these polymers is preferred. Especially preferred is a polymer which is selected from a group comprising EVA, PVA, any other copolymer of ethylene, any other copolymer of propylene, PE, and any other film forming polymer. Such a polymer is usually combustible without any ash or harmful decomposition residues.

In a preferred embodiment of the cigarette paper, the non-coated surface area of the cigarette paper provides a volumetric flow rate in the range of 20-120 cm³min⁻¹ air passing through sample of 1 cm² of this cigarette paper at an applied pressure difference of 1 kP (20-120 C. U.), preferably in the range of 40-100 cm³min⁻¹ (40-100 C. U.), more preferably in the range of 60-85 cm³min⁻¹ (60-85 C. U.). These flow rates have been evaluated as being preferred since the medium flow rate through the cigarette paper could be maintained in the required range to keep the cigarette glowing and/or to maintain a sufficient flow rate along the longitudinal direction of the cigarette, even if other areas of the cigarette paper are coated and—as a result of the (additional) coating—provide a reduced permeability and/or flow rate.

In a preferred embodiment of the cigarette paper, the coated surface area of the cigarette paper provides a volumetric flow rate in the range of 5-80 cm³min⁻¹ air passing through sample of 1 cm² of this cigarette paper at an applied pressure difference of 1 kP (5-80 C. U.), preferably in the range of 8-90 cm³min⁻¹ (8-90 C. U.), more preferably in the range of 10-60 cm³min⁻¹ (10-60 C. U.). Irrespective of the volumetric flow rate of the non-coated surface area of the cigarette paper and the percentage of the coated surface area, the above-defined flow rates ensure that the medium flow rate through the cigarette paper is sufficient to keep the cigarette glowing and/or to maintain a sufficient flow rate along the longitudinal direction of the cigarette to transport the aroma to the user's mouth.

Preferably, the coated surface area of the cigarette paper provides an indicator functionality. Preferably, the indicator functionality is a heat indicator functionality. More preferably, the heat is indicated by a color change. Preferably, the color change is a permanent color change. However, in an alternative embodiment, a temporary color change is preferred. A temporary color change could be useful for indicating hot surface areas, which should not be brought into contact with heat sensitive substances or the user's skin. One advantage of a permanent color change is that by such a permanent color change, the used—and thereby heated—smoking articles could be clearly identified. This is especially suitable for modern smoking articles which are only heated to a desired temperature but not burnt. Without such an indication, it is often difficult to identify used smoking articles and to distinguish them from not-used ones.

With respect to the indicator functionality, it is preferred that the color change of the coated surface area is different to a possible color change of the non-coated surface area. The paper itself could for example change its color as a result of heat treatment. Usually, the color of a cigarette paper changes to brown or brownish, when treated with high temperatures. In this case, no further indication would be necessary because the paper itself indicates usage of the smoking article. However, it is preferred, that the coated surface area changes its color to a different color than the non-coated. This allows special effects and indication of further information for the user. In a preferred embodiment, the name and/or trademark of the supplier of a smoking article could appear on the surface of the cigarette paper after usage.

As the color of the coated surface area is changed after being heated, the consumer can easily understand the heat stick is used as appearance. In addition, this technology can apply design on the cigarette paper which can be seen only after smoking. This could be valuable for the consumer and distinguish such a smoking article with respect to those of other brands.

In a preferred embodiment, the coated surface area forms letters or other symbols which indicate properties of the paper, the smoking article or the tobacco. This allows the user to identify the (smoking) article even after usage.

A further of the above-mentioned problems is solved by a smoking article, which comprises a cigarette paper as described above. A smoking article comprising such a cigarette paper provides an enhanced visual appearance and could easily be recognized by the consumer. It provides a high-value and/or premium-quality appearance and could easily be recognized by the consumer. Because semi-transparent segments of the cigarette paper could be avoided, such a smoking article does not have the disadvantage that the brownish tobacco colour could be seen through the cigarette paper. Thus, brownish areas, which probably could be considered to be dirty or even unhygienic, are obviated. This further increases the high-value and/or premium-quality appearance.

Preferably, the smoking article comprises a mouthpiece and an aerosol generating substrate, wherein the aerosol generating substrate is wrapped in the cigarette paper as described above. Preferably, the aerosol generating substrate is tobacco or comprises tobacco. The aerosol generating substrate is heated or burnt, whereby the aerosol is generated. Wrapping the aerosol generating substrate in a cigarette paper as described above provides the possibility to improve the optical appearance of the product and/or to provide information to the consumer.

Another of the above-mentioned problems is solved by a method for producing a smoking article comprising a cigarette paper having a glossiness of at least 4 GU according to DIN EN ISO 2813:2015 in some parts of its surface and a glossiness of less than 4 GU according to DIN EN ISO 2813:2015 in other parts of its surface, wherein the difference of glossiness between these parts is more than 2 GU according to DIN EN ISO 2813:2015. This method further comprises the step of printing a polymer on parts of the cigarette paper by flexography. Flexography is suitable to apply polymers selectively of these areas, which should be coated. Furthermore, flexography allows very fast printing and a high-throughput. This is especially desired for a mass-product like cigarette papers.

In a preferred embodiment the method comprises the step of selecting a suitable polymer. The polymer is preferably selected from a group comprising EVA, PVA, any other copolymer of ethylene, any other copolymer of propylene, PE, and any other film forming polymer. These polymers have been found to be especially suitable for printing processes, especially for flexography.

It is preferred that the polymer is selected from a group comprising EVA, PVA, any other copolymer of ethylene, any other copolymer of propylene, PE, and any other film forming polymer. Any of these polymers is especially suitable for being applied to the paper by flexography.

In a preferred embodiment of the method, the polymer is printed as emulsion, suspension or in molten form. This facilitates handling and even distribution of the polymer. Preferably, the emulsion, suspension or the molten polymer is dried after its application on the cigarette paper. In a further preferred embodiment, this is performed under at least temporally increased pressure. At least in some cases, the increased pressure further enhances the glossiness of the coated surface area. Furthermore, the polymer could be bonded tighter to the paper.

All disclosed features relating to the method shall apply mutatis mutandis to the cigarette paper and/or the smoking article and all disclosed features relating to the cigarette paper and/or the smoking article shall apply mutatis mutandis to the method.

Further advantages, objectives and features of the present invention will be described, by way of example only, in the following description with reference to the appended figures. In the figures, like components in different embodiments can exhibit the same reference symbols.

BRIEF DESCRIPTION OF THE DRAWINGS

The figures show:

FIG. 1a an image of a tobacco stick, surrounded by a cigarette paper with coated and non-coated surface areas according to the invention;

FIG. 1b a schematic illustration of the tobacco stick of FIG. 1 a;

FIG. 2a a detailed image of the tobacco stick of FIG. 1a with coated and non-coated surface areas;

FIG. 2b a schematic illustration of the tobacco stick of FIG. 1 b;

FIG. 3 an image of a cigarette paper according to the invention with a stripped pattern coated on the paper;

FIGS. 4 and 5 images of possible forms of the coated surface on the cigarette paper.

DETAILED DESCRIPTION

FIG. 1a shows an image of a tobacco stick 1, surrounded by a cigarette paper 10 with coated 11 and non-coated 12 surface areas according to the invention. The cigarette paper 10 surrounds the lateral area of a cylinder 2 (geometrically in more detail: a right circular cylinder) made of tobacco (not shown).

The cigarette paper 10 is partially, namely in the coated areas 11, coated with a glossy coating 13. In the illustrated embodiment, this coating is applied in crossing stripes onto the planar cigarette paper 10, which is then wound around the tobacco cylinder 2. In this curved form of the cigarette paper 10, the coated areas 11 have a helical shape.

This embodiment is further illustrated by the schematic illustration of FIG. 2b . In this illustration, it can be seen that two stripes of coating intersect each other and form a checkered pattern on the cigarette paper 10 and/or the tobacco stick 1.

FIG. 3 shows a further embodiment of the cigarette paper 10. The pattern 14 of the coated areas 11 are stripes. A base paper was coated locally with a polymer. In this embodiment, a polymer was used, which was previously used in the tobacco industry as glue for attaching overlapping ends of a cigarette paper onto each other. The application was performed by printing, in this case by flexography. The polymer was applied at an amount of about 6 g/m² per printed area. In this embodiment about 43% (preferably between 40-50%) of the total upper surface of the cigarette paper 10 was coated with the polymer.

In the embodiment of the cigarette paper 10 shown in FIG. 3, an increased glossiness of 5.46 GU (5.46 Gloss Unit according to ISO 2813) of the coated area 11 could be determined. In contrast thereto, the glossiness of the non-coated area 12 was measured to be only 2.68 GU. As it can be derived from FIG. 3, the difference between the above-mentioned values for the glossiness of the coated 11 and the non-coated area 12 could easily be noticed by the human eye. The opacity of the coated 11 and the non-coated 12 area was measured, too. The difference between the measured opacity of these areas was very low. The opacity of the coated area 11 was determined to be 74.9% and the opacity of the non-coated area 12 was measured to be 75.6%.

The combustion properties of the cigarette paper 10 shown in FIG. 3 have been determined. It has been found that at a coating ratio of 43% of the total upper surface of the cigarette paper 10, the cigarette paper 10 is still combustible and no negative effect on the LIP effect (Lower Ignition Propensity) and burning rate was determined. In contrast thereto, it was found, that very high coating ratio of up to 100% of the total upper surface of the cigarette paper 10 could result in reduced combustibility. A coating ratio of 100% results to 0 in a FASE test. Furthermore, the porosity was decreased dramatically for such a highly coated base paper from about 80 to only 5 CU. In contrast thereto, the coating ratio of 43% of the cigarette paper 10 as illustrated in FIG. 3 results in a porosity of about 45 CU.

FIGS. 4 and 5 show images of possible embodiments of the coated surface 11 on the cigarette paper 10. Both cigarette papers differ on the pattern 14 of the coating. In both embodiments, the pattern forms letters and/or other symbols. A base paper providing a permeability of about 60 CU was coated locally with e polymer. The application was performed by printing, in this case by flexography. The polymer was applied at an amount of about 4.3 g/m² per printed area. While the local coating 12 of the cigarette paper 10 shown in FIG. 4 indicates the supplier of the cigarette paper 10, the pattern 14 of the local coating 12 of the cigarette paper 10 shown in FIG. 4 indicates special proprieties of the paper as such and/or the tobacco to be enclosed.

The applicant reserves his right to claim all features disclosed in the application document as being an essential feature of the invention, as long as they are new, individually or in combination, in view of the prior art. Furthermore, it is noted that in the figures features are described, which can be advantageous individually. Someone skilled in the art will directly recognize that a specific feature being disclosed in a figure can be advantageous also without the adoption of further features from this figure. Furthermore, someone skilled in the art will recognize that advantages can evolve from a combination of diverse features being disclosed in one or various figures.

LIST OF REFERENCE SYMBOLS

1 tobacco stick

2 cylinder

10 cigarette paper

11 coated surface area

12 non-coated surface area

13 coating

14 pattern 

1. A smoking article wrapper, such as a cigarette paper, comprising at least one coated surface area and at least one non-coated surface area, wherein the smoking article wrapper is combustible and provides a mean volumetric flow rate of at least 40 cm³min⁻¹ air passing through a sample of 1 cm² of the smoking article wrapper at an applied pressure difference of 1 kPa, the at least one coated surface area of the smoking article wrapper provides a glossiness of at least 4 GU according to DIN EN ISO 2813:2015, the at least one non-coated surface area provides a glossiness of less than 4 GU according to DIN EN ISO 2813:2015 and a difference of glossiness between the at least one coated surface area and the at least one non-coated surface area is more than 2 GU according to DIN EN ISO 2813:2015.
 2. The smoking article wrapper according to claim 1, wherein: the glossiness of the at least one coated surface area of the smoking article wrapper is between 4-10 GU, according to DIN EN ISO 2813:2015.
 3. The smoking article wrapper according to claim 1, wherein: the glossiness of the at least one non-coated surface area is between 1-4 GU according to DIN EN ISO 2813:2015.
 4. The smoking article wrapper according to claim 1, wherein: a difference of opacity between the at least one coated surface area and the at least one non-coated surface area of the smoking article wrapper is less than 2%.
 5. The smoking article wrapper according to claim 1, wherein: an opacity of the at least one coated surface area of the smoking article wrapper is more than 70%.
 6. The smoking article wrapper according to claim 1, wherein: a percentage of the at least one coated surface area is less than 80% of a total surface area of the smoking article wrapper.
 7. The smoking article wrapper according to claim 1, wherein: the at least one coated surface area comprises a coating of 0.5 to 20 g/m².
 8. The smoking article wrapper according to claim 1, wherein: the at least one coated surface area comprises a polymer as a coating agent, wherein the polymer is at least one of EVA, PVA, any other copolymer of ethylene, any other copolymer of propylene, PE, or any other film forming polymer.
 9. The smoking article wrapper according to claim 1, wherein: the at least one non-coated surface area of the smoking article wrapper provides a volumetric flow rate in a range of 20-120 cm³min⁻¹ air passing through a sample of 1 cm² of the smoking article wrapper at an applied pressure difference of 1 kP.
 10. The smoking article wrapper according to claim 1, wherein: the at least one coated surface area of the smoking article wrapper provides a volumetric flow rate in a range of 5-80 cm³min⁻¹ air passing through a sample of 1 cm² of the smoking article wrapper at an applied pressure difference of 1 kP.
 11. A smoking article comprising the smoking article wrapper according to claim
 1. 12. The smoking article according to claim 11, further comprising: a mouthpiece and an aerosol generating substrate, wherein the aerosol generating substrate is wrapped in the smoking article wrapper.
 13. A method for producing a smoking article comprising a smoking article wrapper having a glossiness of at least 4 GU according to DIN EN ISO 2813:2015 in first parts of a surface of the smoking article wrapper and a glossiness of less than 4 GU according to DIN EN ISO 2813:2015 in other second parts of the surface, wherein a difference of glossiness between the first and second parts is more than 2 GU according to DIN EN ISO 2813:2015, the method comprising: printing a polymer on areas of the smoking article wrapper by flexography.
 14. The method according to claim 13, wherein: the polymer is at least one of EVA, PVA, any other copolymer of ethylene, any other copolymer of propylene, PE, or any other film forming polymer.
 15. The method according to claim 13, wherein the step of printing includes printing the polymer as emulsion, suspension or in molten form, and the method further comprises drying the polymer after the step of printing.
 16. The method according to claim 15, wherein the step of drying is performed under at least temporally increased pressure. 